Severe thunderstorms and a tornado or two could arrive late Tuesday (Nov. 29) and early Wednesday in the New Orleans area, the North Shore, the River Parishes and the Baton Rouge area, according to National Weather Service forecasters. The risk of severe thunderstorms is greater for Baton Rouge, west St. Tammany Parish and the Florida Parishes, according to the Storm Prediction Center, and slight along the south shore of Lake Pontchartrain and in east St. Tammany and in the River Parishes.

"The time of most concern will be during the overnight hours," forecasters with the agency's Slidell office said in a Tuesday morning hazardous weather outlook message. "The main concerns will be damaging wind gusts, large hail and isolated tornadoes."

Forecasters say the storms could dump as much as 2 inches of rain across the area through Wednesday The thunderstorms are expected to end on Wednesday morning, as the threat of severe weather moves east with a strong cold front.

The risk of severe weather results from a complicated combination of the warm air ahead of the cold front, the surface low pressure along the front and a trough of low pressure higher in the atmosphere. The combination is increasing the chances of wind shear that can create rotation in clouds, resulting in funnels or tornadoes, either as individual storm cells form in advance of the front or in cells or bowed areas of a squall line that might develop as the front moves across the area overnight.

Before Tuesday at noon, temperatures had already hit 81 in both New Orleans and Baton Rouge. That exceeded the forecast in both locations of upper 70s.

On Wednesday, expect highs only near 70 in New Orleans and in the upper 60s in Baton Rouge, dropping into the low 60s on Thursday and Friday. Forecasters say there's a chance of showers and thunderstorms beginning early Saturday and lasting through Monday.